The exemplary embodiments of the present invention generally relate to communication systems. More particularly, the exemplary embodiments relate to automatic error control in mobile, over-the-air communication systems.
In mobile, over-the-air communications, the combination of multipath effects and motion can be harmful to data communications. Multipath effects will cause the signal strength to vary dramatically from one receiving location to another receiving location, even when the locations are just a few feet apart. Motion, such as in mobile communications where the transmitter and/or receiver are moving, can introduce clicks on the demodulated waveform due to phase changes associated with the varying signal level. The multipath and motion combination can also introduce bit errors, resulting in an irreducible error rate. No matter how strong the signal is, there will be a high residual error rate.
Prior attempts to correct the errors resulting from multipath and motion in mobile, over-the-air communication systems have typically employed higher RF power, wider channel size, and more spectrally intrusive modulation schemes. Since messages sizes are rarely known a priori, it would be advantageous not to limit the size of all messages by encumbering every message with maximum error control, or by skipping strong error control for all messages, because some could be larger than others.
Accordingly, it would be desirable to provide a system that addresses at least some of the problems identified above.